Abstract: With the rapid development of space technology, the reliability and safety of spacecraft pipeline systems have become increasingly critical. This paper systematically reviews the research progress on in-orbit repair technologies for spacecraft pipeline systems worldwide, mainly covering nondestructive testing and thermal manufacturing repair technologies. The applicability of arc welding, laser processing, electron beam processing, and brazing to spacecraft pipeline repair is comparatively analyzed, and a multi-technology collaborative repair scheme is proposed. Among nondestructive testing methods, ultrasonic testing and ultrasonic leak detection are used for internal defect characterization and leak localization, respectively. Regarding thermal manufacturing repair technologies, hollow-tungsten-electrode argon arc welding shows promising application potential but remains technically immature; electron beam repair shows engineering application potential because of its inherent compatibility with vacuum environments; laser repair can operate under various environmental conditions, and related research is progressing steadily; and brazing is suitable for joining thin-walled components and dissimilar materials and shows potential for space applications. Electron beam repair, laser repair, and brazing provide process options for spacecraft pipeline repair, but their environmental compatibility, joint load-bearing capacity, and leak tightness require further validation. This study provides a reference for the future development of spacecraft pipeline maintenance technologies and offers a reference for the design of next-generation in-orbit spacecraft maintenance equipment.